ACD systems distribute calls--whether inbound or outbound--for handling to any suitable ones of available call-handling agents according to some predefined criteria. In many existing systems, such as the Lucent Technologies Definity.RTM. ACD system, the criteria for handling the call from the moment that the ACD system becomes aware of the call until the call is connected to an agent are customer-specifiable (i.e., programmable by the operator of the ACD system) via a capability called call vectoring. Normally in present-day ACD systems, when the ACD system's controller detects that an agent has become available to handle a call, the controller identifies all predefined call-handling skills of the agent (usually in some order of priority) and delivers to the agent the highest-priority oldest-waiting call that matches the agent's highest-priority skill. Generally the only condition that results in a call not being delivered to an available agent is that there are no calls waiting to be handled.
Most present-day call-distribution algorithms focus on being "fair" to callers and to agents. This fairness is reflected by the standard first-in, first-out call to most-idle-agent assignment algorithm. Skills-based routing improves upon this basic algorithm in that it allows each agent to be slotted into a number of categories (splits) based on the agent's skill types and levels.
The primary objective of call-distribution algorithms is to ultimately maximize call center performance. That may involve minimizing cost, maximizing call throughput, and/or maximizing revenue, among others. For example, when a new call arrives, the call should be handled by an agent who either has the ability to produce the most revenue or can handle the call in the shortest amount of time. Also, when an agent becomes available to handle a new call, the agent should handle either the call that has the possibility of generating the most revenue or the call which the agent is most efficient in handling. A telephone call-handling system having such functionality is disclosed in U.S. Pat. No. 5,299,260. However, this system is limited in its capabilities to truly maximize call center performance: it permits only one criterion or metric to be used at any one time to select an agent for handling an individual call, while call center performance is typically a multi-faceted function that involves a number of criteria or metrics.